Cropping Images in Photoshop using the Crop Tool And Rectangle Marquee Tool Tutorial, and An Introduction to aspect ratio

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“Cropping Images in Photoshop using the Crop Tool And Rectangle Marquee Tool Tutorial” is part of my Photoshop book “Learn Photoshop CC With Pictures”, which is more revised and covers more concepts than the online tutorials, feel free to check out the book by visiting my Learn Photoshop CC With Pictures Book Page.


Cropping images in Photoshop. And adjusting their sizes of images. Are among of the basic and most common features to do with Photoshop. As well as other graphics software. To the degree that some Photoshop courses start with how to do that right away. Right now, I am going to show you different ways of cropping images. I will also going to explain the concept of aspect ratio and how adjusting the aspect ratio is useful.

What cropping images means?

According to Wikipedia. Cropping images refers to the removal of the outer parts of an image to improve framing. In my own definition. It is taking a certain part of the picture and get rid of the rest. If that didn’t make sense to you, take a look at the following penguins picture, there are 4 adult penguins in it:-

Penguins

If I only want the penguin at the right and I don’t need the rest of the picture. I could crop the picture to contain only that penguin:-

Penguins-Cropped

There are many techniques for cropping images like that. The simplest way to do it at all is to use The Crop Tool Crop-Tool

Cropping images in Photoshop using the Crop Tool Crop-Tool

The crop tool is the easies way to crop a picture, to demonstrate that, I will show you how I cropped the penguins picture above using that tool. All you have to do to crop a picture is to follow these steps:-

  • Select The Crop tool Crop-Tool from the Tools Panel
  • Click and drag around the part you want to crop. Exactly the same way you make selections using the Rectangular Marquee Tool. The picture will look like that:-

Crop-Tool-1

The illuminated area is where the picture will become like once you are done cropping, and the black area(called the “Shield”) is the parts that will be discarded once you are done cropping.

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  • You can adjust the rectangle as much as you want at this stage. So you don’t need to worry about making mistakes here. I adjusted the selection here to contain only the Penguin I wanted and nothing else

Crop-Tool-2

After you are done adjusting the area you want to crop. You can do one of two things now:-

  • Press Enter on your keyboard and you will end up with the part of the picture you selected
  • Or If you changed your opinion and didn’t want to want to cancel the cropping altogether. You could press Escape (The Esc button at the corner of the keyboard), to cancel the cropping operation.
The penguin we wanted, fit as a fiddle~
The penguin we wanted, fit as a fiddle~

Candy-Tip-Icon

Candy Tip:- Instead of pressing Enter Or Escape to make or cancel the operation, you could press the √ or ⍉ on the Crop Tool option bar to complete or cancel the cropping.Crop-Tool-4

As you just saw the crop tool cropped the image really nicely. But there is a nicer way to do it. Which is to adjust the Aspect Ratio of the area to be cropped, which has many applications, as you will see below.

But before I go about how to do that, let me first introduce you to the concept of Aspect Ratio.

About Aspect Ratio

Aspect ratio is the term that refer to how much the width of a rectangle is compared to the its height. For example. The Aspect Ratio of a square is always 1:1 (one to one). Meaning that for each Centimetre(or any unit really) of the width of the square, there is 1 centimetre of height to it. In other words, if the width of a square is 10 centimetre, it means that the height of the square is also 10 centimetre. Keeping this aspect ratio is important for a square to remain a square, or else it will become a rectangle.

Knowing the aspect ratio means that if you know the width or the height of a rectangle, you can know the other quite easily, can you tell me what is the height of the square whose width is 3.14 cm? :)

There is no difference in saying that the aspect ratio of the square is 1:1 or 10:10, what matters is the relationship between the two numbers, not the numbers themselves.

Square-Aspect-Ratio

Now let’s take a look at the Aspect Ratio of rectangles, when we say that the Aspect Ratio of a rectangle is 2:1 it means that for each 2 Centimetres of the width of the rectangle, there is 1 centimetre to the height of that rectangle. In other words, the width of the rectangle is double its height, and it will look like that:-

Rectangle-1-Aspect-Ratio

The width of such rectangle is double its height, meaning it has the aspect ratio os 2:1, or 20:10.(Or even 30:15, it doesn’t matter, as long the first number of double the second one).

And if we said that the aspect ratio of a certain rectangle is the opposite, 1:2 instead of 2:1, it basically means that the height of a rectangle is double the width of the rectangle. And it will look like that:-

Rectangle-2-Aspect-Ratio

To create the last image, I just had to rotate the picture of the previous example~

Let’s take another example, when we say that the Aspect Ratio of a rectangle is 2.5:1, it means that for each 2.5 centimetre of its width, there is 1 centimetre to its height. To make this aspect ratio easier to understand, I will multiply the numbers by 2, and now the aspect ratio becomes 5:2 instead of 2.5:1. Meaning that for each 5 centimetre of the width of the rectangle, there is 2 centimetre to its height (you could have multiplies it by 3 or 4 if you want, I just choose 2 because it produces the best numbers in my opinion).

The width of the following rectangle is two and half its height. The colours segmentation of the width makes that more obvious.

Aspect-Ratio-5-2 copy

This is all nice and all, but what use does it really have?

I hope all the repetition of the concept has made you familiar of it by now. And you are most likely wondering how knowing the Aspect Ratio could benefit you at all. Lets say your screen resolution is 1366×768 pixels (there are many ways to get to know that, one of them is to go to http://www.whatismyscreenresolution.com/ and it will display your resolution for you). Meaning that the width of your screen is 1366 pixels and the height is 768 pixels.

Suppose you want to change the background picture of your desktop. Ideally, if you have a picture that is 1366×768 pixels you are good to go. And the background will fit to your screen right away.

Fit-To-Screen

But if your picture is like 2000 X 1500 Pixels, like this one:-

Llama

Setting the background to that picture will make it stretch and it won’t look nice at all. That’s because it has a different aspect ratio than your screen resolution. See how the poor Llama got stretched. Depending on the picture and how different the aspect ratio from your screen is, the distortion can be more or less than this example.

Fit-To-Screen-2
Here, the 2000 X 1500 Llama picture doesn’t fir well with the 1366 X 768 screen. And it is all stretched because of the different aspect ratio it has from the screen.

The solution to this problem is to crop your picture so it will have the same aspect ratio as your screen. Which can be done using the Crop tool, as well as your old friends, the Rectangle Marquee Tool.

Using the Crop Tool to crop a picture to a certain Aspect Ratio

Cropping our 2000 X 1500 image so that it will fit to our 1366 X 768 Screen is very easy to do with the crop tool. All you have to do is to specify the aspect ratio you want before cropping the image, here is how to do that:-

  • Select The Crop Tool Crop-Tool from the tools Panel.
  • In the Crop Tool options, simply entering the aspect ratio you want in the Width & Height fields will allow you to make selections that abide by that ratio.

Cropping-Aspect-Ratio-1

  • Since we want to crop the picture to fit with our 1366 X 768 screen, simply entering those values will do.

Certain-Size-Selection-11

  • Now drag to select the area you want to crop, after you make the selection, feel free to adjust the area you want to crop, after you are done, press Enter, and Photoshop will crop the picture for you.
  • Here is what I got:Cropping-Aspect-Ratio-3
  • And here is how it fits to the screen of the laptop, without being stretched and all.

Fit-To-Screen-3

Using the Rectangle Marquee Tool For Cropping images

The Marquee Selection Tool Marquee-Selection-Tool (And other selection tools as well) can be used as cropping tools as well as for selection. And as you know by now, it can be used to crop a picture to fit a certain aspect ratio, before we get to do that, I will show you how to do normal cropping first:-

  • Select the Rectangle Marquee Tool Marquee-Selection-Tool from the tools panel
  • Select the Area you want to crop in your picture, here I am interested in the having the brownie in its own picture

Brownie-Selection-1

  • From the main menu, select, Image -> Crop, and Photoshop will crop the picture to the part you selected.

Brownie-Selection-2

Easy, right? So far, there is not much different between the Marquee Selection Tool and the Crop tool. And doing cropping seems much easier using the Crop tool, giving that it allows you to adjust the area you selected after you make your selection. But it doesn’t hurt to know both, seeing how you may want to crop an image based on a certain selection you already made, like selecting a man and cropping the image to have only the parts that contains him.

Using the Rectangle Marquee Tool to crop a picture to a certain Aspect Ratio

Back to the problem of the Llama picture and its aspect ratio that don’t fit with our 1366×768 screen. Cropping the image to fit that aspect ratio using the Crop Tool solved that problem. Here is how to do that with Rectangle Marquee Tool as well:-

  • Select the Rectangle Marquee Tool Marquee-Selection-Tool from the Tools Panel
  • From the Style menu in the Marquee Tool Options, select “Fixed Ratio”, this will force you to only make selections of a certain aspect ratio. Based on the “Width” And “Height” options:-

Style-MenuStyle-Menu-2

  • The Width & Height options makes you specify the aspect ratio to use when you make a selection, the aspect ratio here is 1:1, meaning that it will create a square selection.Style-Menu-3
  • Since we want the cropped picture to abide by the 1366×768 aspect ratio of our screen, setting the width to 1366 and the height to 768 will most likely solve out problem. So let’s do enter 1366 into the Width field and 768 in the height fields, just like we did with the Crop Tool earlier.

Style-Menu-4

  • But it turns out that Photoshop won’t allow you to enter 1366 in the width field. As it doesn’t allow any value that exceed 999.99. But that’s not a problem, instead of inserting 1366 & 768 into he fields, we will divide both numbers by 10. Which will get is 136.6 & 76.8 which are a suitable numbers to be inserted in the Width & Height Fields.
Style-Menu-5
The Width & Height fields after adjusting the aspect ratio.
  • Now we are free to make the part of the Llama picture we want to crop, simply click and drag like you make any rectangular selection, the selection size will be restricted to fit the aspect ratio, here is the Llama selection I made:-

Style-Menu-6

Candy-Tip-Icon

Candy Tip:- You can move the selection a little bit using the arrow keys ←↑→↓ on your keyboards, holding shift while you are pressing the keys will make the selection moves faster.

 

  • Now, select Image -> Crop from the main menu, and Photoshop will crop the selection for you. The new image I got had the resolution of 1957 X 1000, which fits to the aspect ratio of out monitor. Though that won’t seem obvious until we set it as a background, here is the picture I got:-

Cropped-Llama

  • And here is how it fits to the screen of the laptop, without being stretched and all.
Cropping images in Photoshop is a great way to change the aspect ratio of a picture to fit a computer screen
Cropping images in Photoshop is a great way to change the aspect ratio of a picture to fit a computer screen

Making selections of a certain size

Suppose that instead of making selections to crop that abide by a certain aspect ratio, you wanted to make a selection that’s of a certain size, say 1000 X 1000 pixel, the Rectangle Marquee Tool allows you to do that, here is how:-

  • Select the Rectangle Marquee Tool Marquee-Selection-Tool from the Tools Panel
  • From the Style menu in the Marquee Tool Options, select “Fixed Size” from the Style menu, this option allows you to make selection that is of a certain size

Style-Menu-2

  • Enter the size of the selection you want to make, I typed 1000 px in both fields to make a 1000 X 1000 selection.

Certain-Size-Selection-1

  • Just click on the document where you want the upper-left corner of the selection to be, and Photoshop will make the selection to you
Certain-Size-Selection-2
A 1000 X 1000 Selection I made using the Rectangle Marquee Tool
  • Now, select Image -> Crop from the main menu, and Photoshop will crop the selection for you, here is the final 1000 X 1000 picture of the teapot I got:-

Certain-Size-Selection-3

Candy-Tip-IconCandy Tip:- You can make selections by units other than pixel using the Marquee Selection Tool. To do that, simply type CM  or IN or any unit you want in the Width or Height Fields. Here I set Photoshop to make a 20 X 20 inch selection:-

Certain-Size-Selection-4

Here are the other units you could use:-

Photoshop Measurement Units
Unit Name Photoshop Short Name
Pixels px
Inches in
Centimeters cm
Millimeters mm
Points pt
Picas pica

You are going to encounter these units in more than one place in Photoshop~

More on the Crop Tool & Cropping

As always, the tutorial is officially done. But I still have a few things I can teach you, if you don’t feel like it right now, feel free to skip to the examples section by clicking here.

Changing the appearance of the black area that will be discarded

The Crop Tool allows you to change the colour of the area that is going to be discarded in more than a way using the options on the tops of the screen that appears while you are doing the cropping. Initially, the options look like this:-

Cropped-Tool-Options-2

First let’s take a look at the Color option, which allows you to change the colour of the area that is going to be cropped, which is black by default

Cropped-Tool-Options-3

Cropped-Tool-Options-1

Clicking on this option will open the colour picker

Cropped-Tool-Options-4

Which will allow you to choose the colour for the cropped out area. Here is how I changed it it to green:-

Cropped-Tool-Options-5

The shield check box determines whatever the cropped out area is dimmed out or not (It is called “Shield” because that’s what the cropped out area is called).

Cropped-Tool-Options-6

Here is how it looks like when the option is unchecked. See how the shield disappeared:-

Cropped-Tool-Options-7

And the opacity option determines how much transparent the dimmed out area will be:-

Cropped-Tool-Options-8

Click on the picture to view it on full size

Cropped-Tool-Options-9

And the Crop Guide Overlay menu determines how divided the cropped area will be

Cropped-Tool-Options-10

This option can be either “Not divided at all”, “Divided By Third”, Or “Divided By Grid”. Here is how each of the options will look like:-

Click on the picture to view it on full size

 Cropped-Tool-Options-11

Automatically Set The Aspect Ratio Of The Crop Tool To One Of An Existing Image

Again, suppose you want to change the background picture of your computer. But instead of going through all the trouble of calculating the aspect ratio. So that you could crop the new image as needed. You could use another background picture to automatically set the aspect ratio. And then you could crop the soon-to-be-background picture right away. Here is how to do that:-

  • Open the other background picture, or any picture you went to “capture” its aspect ratio. Let’s assume it is this pictureFront-Image-2
  • Select The Crop Tool Crop-Tool from the Tools Panel
  • From the Crop Tools option, simply click on the “Front Image” button. And the crop tool will immediately have the aspect ratio of the image you are working on. Don’t worry if you didn’t understand what numbers you got means, they simply represent the aspect ratio of the image you had at the front the moment you clicked the button.

Front-Image-1

Front-Image-3

Simply drag using the Crop tool and after you are done cropping the image, you will end up with a picture with the correct aspect ratio. Which be used as a background image without any problem

Front-Image-4Front-Image-5

Cropping a non-rectangular selection

As you have most likely guessed, the same way you can make a selection using the Rectangle Marquee Tool and then cropping it. You could do the same way using any of the other selection tool. But be aware that you will always end up with a rectangular image at the end, one that best fits around the the area you selected.

So, simply cropping the circle in this picture:-

Non-Rectangular-Selection-1

Will produce the following one:- Non-Rectangular-Selection-2

Examples:-

Cropping a picture to fit the Aspect Ratio of an online avatar.

One of the online forums I am registered at has avatar size of 125 X 100, which requires me crop the part I want to create the avatar of to fit that aspect ratio. Let’s say we have the following Polar Bear picture. And I want to create an avatar of the bear facePolar-Bear-Avvy

All I have to do is to set the aspect ratios to 125 X 100, and then select the bear face(I used the Rectangle Marquee Tool here, but you could do the same with the Crop Tool as well)

Polar-Bear-Avvy-2

Then cropping the picture by choosing Image -> Crop got me the following picture:-

Polar-Bear-Avvy-3

Which I now could resize to 125 X 100 easily by choosing Image -> Image Resize dialog from the main menu. Which is covered in the following tutorial.

Would you like to learn Photoshop?

Check my Photoshop book Learn Photoshop CC With Pictures which contains a full course on how to use Photoshop in the simplest way possible.

See Also

SweetMonia
I am an anime artist, and huge fan of digital art. I love drawing with pencils too. But I rarely do that anymore nowadays. Since some aspects of digital art can be tricky, I try my best to explain the concepts as easily as possible.

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